'Bypass Brain': How Surgery
May Affect Mental Acuity

By

Melinda Beck

Updated June 10, 2008 12:01 a.m. ET

Aides to Bill Clinton last week vehemently denied speculation that the former president's intemperate remarks on the campaign trail were due to mild cognitive damage from his quadruple-bypass surgery in 2004.

"This theory is false and is flatly rejected by President Clinton's doctors, who say he is in excellent shape...." the statement said.

But the condition dubbed "pump head" or "bypass brain" has long been recognized by doctors, even if they seldom warn patients about it.

Discuss

Have you or a family member had cognitive problems after bypass surgery? How long did it last? Share your experiences.

Symptoms include short-term memory loss, slowed responses, trouble concentrating and emotional instability. In a landmark study published in the New England Journal of Medicine in 2001, researchers at Duke University Medical Center tested 261 patients before and after bypass surgery and found that 53% of them had significant cognitive decline when they were discharged -- and 42% still suffered from it five years later.

"I have hundreds of patients whose families will say, 'Dad's not the same as he was before surgery,'" says John McDougall, an internist in Santa Rosa, Calif., who suggested the Clinton connection in his online newsletter in April. Many readers wrote in, telling of relatives crying uncharacteristically and making embarrassing outbursts after bypass surgery. Other patients have complained of subtle effects, such as losing their edge at chess or no longer being able to handle complex legal cases.

One explanation is that when a patient's blood is pumped through a heart-lung machine during bypass, tiny air bubbles, fat globules and other particles may enter the bloodstream. The pump can also damage platelets, which form clumps, and clamping the aorta loosens bits of plaque. That debris can travel to the brain and clog tiny capillaries, forming microscopic strokes.

Heart-Breaker

Vital statistics on heart disease.

Coronary artery disease caused 451,325 deaths in 2004 -- a 33% drop since 1994. But it is still the leading cause of death in the U.S.

To reduce such damage, cardiac surgeons developed "off-pump" techniques to operate with the heart still beating; that now accounts for about 20% of all U.S. bypass operations. Some hospitals market it for patients who want to avoid mental fog. But studies have found that cognitive decline is just as common five years later in patients who had on-pump or off-pump bypasses.

Therein lies some controversy. There's little dispute that heart surgery does cause short-term cognitive problems -- anesthesia alone can do that, particularly in older patients. But recent studies suggest that the cognitive decline years later may be due more to the underlying artery disease than to the effects of surgery.

Researchers at Johns Hopkins School of Medicine have been following 152 bypass patients, another 92 treated with medication or stents and a group of healthy controls. They reported in the Annals of Neurology last month that after six years, all the patients with coronary-artery disease had cognitive decline -- no matter how they were treated. The healthy patients didn't.

"We think that atherosclerosis of the heart rarely occurs in isolation," says neurologist Ola Selnes, the lead author. "Patients usually have some in their brains as well."

There are still many unknowns. Depression is very common in heart patients and also causes cognitive decline. So does advancing age, and bypasses are being done on ever-older patients. No one knows if the damage is reversible; studies are ongoing to see if drugs or behavioral therapy can help.

All of this complicates a key question: Should the possibility of cognitive damage be a factor in deciding how to treat heart disease? There are many vested interests at stake. Some critics think bypass surgeries (at $90,000 and up) are done too often. Makers of stents and statins say they can treat heart disease with fewer cognitive risks. Cardiac surgeons say the most serious blockages need bypass and dismiss "pump head" as a misnomer.

"For the vast majority of patients facing life-saving heart surgery, this problem of possible post op cognitive decline should be viewed as a minor and transient risk...." wrote Timothy Gardner, a cardiothoracic surgeon and president-elect of the American Heart Association, in an email.

One clear message is that no matter how the heart is treated, it's also crucial to control the underlying artery disease. In one small German study, bypass patients who lowered their cholesterol, blood pressure and blood sugar and stopped smoking didn't experience cognitive decline five years later.

"Too many patients think we can fix their problem with surgery and then they're free to go back to McDonald's again," says Dr. Selnes. "That's probably the wrong message."

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